RELATIONSHIP BETWEEN MEZEREIN-MEDIATED BIOLOGICAL RESPONSES AND PHORBOL ESTER RECEPTOR OCCUPANCY

  • 1 January 1983
    • journal article
    • research article
    • Vol. 43  (1) , 11-14
Abstract
The phorbol ester analog, mezerein, is a weak complete and stage 1 tumor promoter; however, it is a potent as the most active phorbol esters as a 2nd stage promoter and inflammatory agent. Therefore, mezerein is a useful compound for studying responses associated with stage 1 or stage 2 promotion. In G-292 [human] osteosarcoma cells in culture, mezerein is 25-fold more potent in causing a decrease in binding of epidermal growth factor to its specific cellular receptor than in inducing prostaglandin E2 production. This differentiation potency for these 2 actions was not noted for other phorbol esters. Mezerein apparently interacts with the major phorbol dibutyrate receptor to increase prostaglandin E2 production and also, either with a distinct cellular target with a higher affinity or the same target with increased efficacy, to cause a decrease in the binding to epidermal growth factor. These human osteosarcoma cells thus provide a model system to facilitate analysis of phorbol ester receptor heterogeneity.